The Pediatric Rheumatology Tissue Repository (PRTR), a funded component of a PSO rheumatic disease core center, assists local and national investigators in specimen collection, processing, storage and distribution of biospecimens for rheumatic diseases-related studies. The principal functions of this core are: ? To collect, process and maintain biological specimens from patients with pediatric rheumatological and related musculoskeletal conditions as well as from relevant control populations for research purposes. Samples collected include blood, urine, synovial fluid, synovial tissue, hair and saliva. Products derived from these collections are suitable for genetic, genomic, proteomic, immunologic function and biomarker studies. ? To optimize the availability and potential for use of sample collections. Collection, processing and storage practices are optimized to meet current and future study needs and when possible standardized to be consistent with other national and international efforts. ? To provide high quality samples in an appropriate format for investigators conducting IRB-approved basic and translational studies in pediatric rheumatologic disease. Informatics solutions for sample storage documentation will allow accurate and appropriate use. Current systems have been optimized to allow information relative to consent, source of collection (study, extemal site, type of sample, etc), and specifics of handling/processing as well as prior use to be considered when accessing samples.